<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <button>点击清除定时器</button>
</body>

<script>
    let timer = setTimeout(function() {
        console.log('爆炸了');
    }, 5000)
    let but = document.querySelector('button');
    but, addEventListener('click', function() {
        clearTimeout(timer);
        console.log('定时器清除');
    })
</script>

</html>